Acidity constants from DFT-based molecular dynamics simulations.

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Theoretical Chemistry

Background:

• Calculating acidity constants is crucial for understanding chemical reactions.
• Traditional methods can be limited in scope or accuracy for diverse chemical systems.

Purpose of the Study:

• To present and validate a novel computational method for determining acidity constants.
• To demonstrate the method's applicability to a broad spectrum of organic and inorganic acids and bases.

Main Methods:

• Utilizing density functional theory (DFT) based molecular dynamics simulations.
• Employing a half-reaction scheme with formal proton transfer from solution to gas phase.
• Calculating deprotonation free energies from vertical energy gaps for proton insertion/removal.

Main Results:

• The method successfully estimated relative acidity constants and Brønsted pK(a) values.
• Validation was performed on a diverse set of acids and bases covering a 20-unit pK(a) range.
• Thermochemical corrections for biasing potentials were analyzed.

Conclusions:

• The developed DFT-based molecular dynamics method provides a robust approach for calculating acidity constants.
• This method offers accurate predictions for a wide range of acid-base strengths.
• The study validates a powerful computational tool for chemical thermodynamics research.